Buffy, The Vampire Slayer star Michelle Trachtenberg has alleged that show creator Joss Whedon was not allowed to be left alone with her during her time working on the series.

Earlier this week, Buffy and Angel star Charisma Carpenter spoke out against Whedon in a lengthy Instagram post, accusing the now-56-year-old producer of creating an unpleasant atmosphere on set and being "mean and biting".

Trachtenberg joined the cast of the show as Buffy's young sister Dawn in season five, when the actress was aged just 15, and now she too has come forward to allege that Whedon was "not appropriate" with her.

"I am brave enough now as a 35 year old woman....To repost this," she wrote on Instagram. "Because. This must. Be known. As a teenager. With his not appropriate behavior....very. Not. Appropriate.

"So now. People know. What Joss. Did.

"The last. Comment I will make on this. Was. There was a rule. Saying. He's not allowed in a room alone with Michelle again."

Whedon has still yet to respond to the allegations against him.